JP6423334B2 - Contact-sensitive element including electroactive film, display device including the same, and method for manufacturing electroactive film - Google Patents

Description

  The present invention relates to a touch sensitive element including an electroactive film, a display device including the touch sensitive element, and a method of manufacturing the electroactive film. More specifically, the touch sensitive element includes an electroactive film having excellent dielectric constant and light transmittance. , A display device including the same, and a method for producing an electroactive film.

  In recent years, the use of a touch-type display device that touches and inputs a display device has been generalized in accordance with a user's request to easily use various display devices such as a liquid crystal display device and an organic light emitting display device. ing. In order to provide direct and various touch feedback to a user in a touch-type display device, research for using a haptic device continues. In particular, since the conventional haptic device is attached to the rear surface of the display panel, it is difficult to provide immediate and fine feedback on the user's touch. Accordingly, research is being actively conducted to provide a direct feedback that is sensitive to a user's touch and is various by positioning the haptic device in front of the display panel. In addition, in recent years, research on the operation of various display devices directly and using a haptic device is being promoted together with a flexible display device that has been actively developed.

  Conventionally, as such a haptic device, a vibration motor such as an eccentric motor (ERM) or a linear resonance motor (LRA) is used for a display device. The vibration motor is designed to shake the entire display device. Therefore, in order to increase the intensity of vibration, there is a problem that the weight and size of the vibration motor must be increased, and frequency modulation for adjusting the degree of vibration is difficult, and the response speed is very slow. . In addition, the vibration motor has a disadvantage that it is not suitable for use in a flexible display device.

  In order to improve the above-described problems, shape memory alloys (SMA) and piezoelectric ceramics (Electro-Active Ceramics; EAC) have been developed as haptic device materials. However, the shape memory alloy (SMA) has a slow reaction rate, a short lifetime, and is opaque, and the piezoelectric ceramic (EAC) is easily broken, so that it is difficult to apply to a display device, particularly a flexible display device. there were.

  As a result, haptic device technology using electro-active polymer (EAP) has recently attracted many people. By electroactive polymer is meant a polymer that can be deformed by electrical stimulation and that can repeatedly expand, contract, and bend by electrical stimulation. Among various types of electroactive polymers, a ferroelectric polymer (Ferroelectric Polymer) and a dielectric elastomer (Dielectric Elastomer) are mainly used. For example, examples of the ferroelectric polymer include PVDF (Poly Vinyl Dene Fluoride) and P (VDF-TrFE) (Poly (Vinyl Dene Fluoride) -TriFluorEteen). For example, examples of the dielectric elastomer include a silicon polymer, a urethane polymer, and an acrylic polymer.

  However, a ferroelectric polymer is used for the front surface of a display device because it has excellent dielectric constant and excellent vibration strength at a low voltage, but has very poor optical characteristics including light transmittance. There are difficulties. In contrast, dielectric elastomers are superior in light transmittance and optical properties, but have a relatively low dielectric constant compared to ferroelectric polymers, so the drive voltage is high and the voltage is relatively low, as in mobile displays. There is a problem that it is difficult to use as it is for a low display device.

  As described above, the inventors of the present invention have difficulty in using a conventional dielectric elastomer in a display device such as a mobile display because of a high driving voltage, and a ferroelectric polymer has a low light transmittance, and thus the front surface of the display device. I found it difficult to use.

  The problem to be solved by the present invention is to provide a touch sensitive element including an electroactive film excellent in both dielectric constant and light transmittance, and a display device including the same.

  Another problem to be solved by the present invention is to provide a touch-sensitive element having a low driving voltage and an improved vibration strength by using an electroactive film having a large dielectric constant, and a display device including the same. It is.

  In addition, another problem to be solved by the present invention is to provide a touch-sensitive element that can be arranged on the front surface of a display panel by using an electroactive film having excellent light transmittance, and a display device including the same. It is to be.

  The problems of the present invention are not limited to the problems mentioned above, and still other problems not mentioned will be clearly understood by those skilled in the art from the following description.

  In order to solve the problems described above, a touch-sensitive element according to an embodiment of the present invention is provided. The touch-sensitive element includes an electroactive film containing a siloxane polymer having a fluoro group or a chloro group bonded to at least a part of the main chain, and the electroactive film is subjected to stretching with a stretching ratio of 100% or more. Thus, the dielectric constant is improved by 15% or more than the electroactive film before stretching.

  According to another aspect of the present invention, the electroactive film has a dielectric constant improved by 30% or more than the electroactive film before stretching when subjected to stretching with a stretching ratio of 300% or more. Can do.

  According to still another aspect of the present invention, the siloxane polymer includes (i) a polysiloxane having a terminal substituted with a vinyl group and a silicon-based crosslinking agent having a fluoro group or a chloro group bonded to at least a part of the main chain. Hydrogen or droxy group produced by crosslinking or (ii) polydimethylsiloxane (PDMS) having a vinyl group at its end and a silicon-based crosslinking agent containing hydrogen or hydroxy group in the main chain Can be produced by substituting at least a part of these with a fluoro group or a chloro group.

  According to still another aspect of the present invention, the electroactive film can be uniaxially or biaxially stretched.

  According to still another aspect of the present invention, the electroactive film may have a β-phase structure.

  According to still another aspect of the present invention, the electroactive film can have a multilayer structure in which ferroelectric polymer regions and dielectric polymer regions are alternately stacked.

  According to still another aspect of the present invention, the electroactive film may have a dielectric constant measured at 1 kHz of 7.0 or higher.

  According to still another aspect of the present invention, the electroactive film may have a light transmittance of 85% or more.

  In order to solve the above-described problems, a display device according to another embodiment of the present invention is provided. The display device includes a display panel, a touch panel, and a touch sensitive element. The touch-sensitive element includes an electroactive film containing a siloxane polymer having a fluoro group or a chloro group bonded to at least a part of the main chain, and the electroactive film is subjected to stretching with a stretching ratio of 100% or more. Therefore, it has a dielectric constant improved by 15% or more than the electroactive film before stretching.

  According to still another aspect of the present invention, the electroactive film can be uniaxially or biaxially stretched.

  In order to solve the above-described problems, a method for manufacturing an electroactive film according to still another embodiment of the present invention is provided. A method for producing an electroactive film includes a step of producing a siloxane polymer by cross-linking a polysiloxane represented by Formula 1 and a silicon-based crosslinking agent represented by Formula 2, and a main chain of the produced siloxane polymer. The method includes the steps of producing a substituted siloxane polymer and forming a substituted siloxane polymer by substituting at least a part of the hydrogen or hydroxy group bonded to each other with a fluoro group or a chloro group.

In Formula 1, R ₁ and R ₂ are each independently a C _{1 to} C ₂₀ alkyl group, a C _{1 to} C ₂₀ aryl group, a C _{1 to} C ₂₀ cycloalkyl group, or hydrogen, and m is 1 It is an integer above.

In Formula 2, R _{3 to} R ₇ are each independently a C _{1 to} C ₂₀ alkyl group, a C _{1 to} C ₂₀ aryl group, a C _{1 to} C ₂₀ cycloalkyl group, or hydrogen, and R ₈ is It is hydrogen or a hydroxy group, n is 0 or an integer of 1 or more, and o is an integer of 2 or more.

  In order to solve the above-described problems, a method for manufacturing an electroactive film according to still another embodiment of the present invention is provided. The method for producing an electroactive film includes a step of substituting at least a part of hydrogen or hydroxy group bonded to the main chain of a silicon-based crosslinking agent represented by Chemical Formula 2 with a fluoro group or a chloro group, and a substituted silicon-based crosslinking. A step of producing a siloxane polymer by crosslinking the agent with the polysiloxane represented by Chemical Formula 1, and a step of forming the produced siloxane polymer into a film.

In Formula 1, R ₁ and R ₂ are each independently a C _{1 to} C ₂₀ alkyl group, a C _{1 to} C ₂₀ aryl group, a C _{1 to} C ₂₀ cycloalkyl group, or hydrogen, and m is 1 It is an integer above.

In Formula 2, R _{3 to} R ₇ are each independently a C _{1 to} C ₂₀ alkyl group, a C _{1 to} C ₂₀ aryl group, a C _{1 to} C ₂₀ cycloalkyl group, or hydrogen, and R ₈ is It is hydrogen or a hydroxy group, n is 0 or an integer of 1 or more, and o is an integer of 2 or more.

  According to another aspect of the present invention, the volume ratio for cross-linking the silicon-based crosslinking agent represented by Formula 2 with respect to the polysiloxane represented by Formula 1 may be 9: 1 to 5: 5.

  According to still another aspect of the present invention, the electroactive film thus formed can be further uniaxially or biaxially stretched.

  In addition, the specific matter of embodiment is contained in detailed description and drawing.

  The present invention can provide a touch-sensitive element including an electroactive film made of a siloxane polymer having both excellent dielectric constant and light transmittance.

  In addition, the present invention can provide a touch-sensitive element having a low driving voltage and an improved vibration strength using an electroactive film having a high dielectric constant.

  In addition, the present invention can provide a method for manufacturing a touch-sensitive element that can be disposed on the upper part of a display panel using an electroactive film having excellent light transmittance, and is finally directly connected to a user. Tactile feedback can be transmitted.

  The effect by this invention is not restrict | limited by the content illustrated above, Furthermore, various effects are included in this specification.

It is a schematic sectional drawing for explaining the structure of the touch sensitive element concerning one embodiment of the present invention. It is the figure which showed the crystal structure of the siloxane polymer used by this invention before and behind extending | stretching. 1 is a schematic exploded perspective view for explaining a structure of a display device including a touch-sensitive element according to an embodiment of the present invention. FIG. 6 is a diagram illustrating an example in which a display device according to various embodiments of the present invention can be advantageously used. It is a figure which shows the flowchart of the manufacturing method of the electroactive film which concerns on various embodiment of this invention. It is a figure which shows the flowchart of the manufacturing method of the electroactive film which concerns on various embodiment of this invention. It is a figure which shows the graph of the vibration acceleration measured when applying the voltage of 2 kVpp to the contact sensitive element containing the unstretched electroactive film of Example 1. FIG. It is a figure which shows the graph of the vibration acceleration measured when applying the voltage of 2 kVpp to the contact sensitive element containing the stretched electroactive film of Example 1. FIG. It is a figure which shows the graph of the vibration acceleration measured when applying the voltage of 2 kVpp to the contact sensitive element containing the electroactive film of the comparative example 1. FIG.

  Advantages and features of the present invention and methods of achieving them will become apparent with reference to the embodiments described in detail below in conjunction with the accompanying drawings. However, the present invention is not limited to the embodiments disclosed below, and should be realized in various different forms, and the embodiments are merely to make the disclosure of the present invention complete. The present invention is provided only for a person who has ordinary knowledge in the technical field to which the present invention pertains to fully understand the scope of the invention, and the present invention is only defined by the scope of the claims.

  When interpreting the constituent elements according to the present invention, it is analyzed that an error range is included even if there is no other explicit description. In the case of the description of the positional relationship, for example, when the positional relationship between the two parts is described as “to up”, “to top”, “to bottom”, “to side”, etc., “immediately” or One or more other parts may be located between the two parts, unless “direct” is used.

  For example, first, second, etc. are used to describe various components, but these components are not limited by these terms. These terms are only used to distinguish one component from another. Accordingly, the first component referred to below can be the second component within the technical idea of the present invention.

  Like reference numerals refer to like elements throughout the specification. The size and thickness of each component illustrated in the drawings are illustrated for convenience of explanation, and the present invention is not necessarily limited to the size and thickness of the illustrated component. .

  The features of the various embodiments of the present invention can be combined or combined partly or wholly with each other, and various technical interlocks and drives are possible, each embodiment being independent of each other. It may be feasible or may be feasible together by correlation.

  In this specification, the electroactive film means a film that can contract or expand when a voltage is applied to transmit a vibration feeling. In the present specification, the touch-sensitive element means an element that can transmit tactile feedback to the user in response to the user's contact with the touch-sensitive element.

  Hereinafter, various embodiments of the present invention will be described in detail with reference to the accompanying drawings. In the present specification, “*” means the same or different moieties combined with different repeating units or chemical formulas.

  FIG. 1 is a schematic cross-sectional view for explaining the structure of a touch-sensitive element according to an embodiment of the present invention. As shown in FIG. 1, the touch-sensitive element 100 according to an embodiment of the present invention includes an electroactive film 110, a first electrode 121 disposed at a lower part of the electroactive film 110, and an upper part of the electroactive film 110. A second electrode 122 is provided.

  The electroactive film 110 is disposed between the first electrode 121 and the second electrode 122 and plays a role of inducing vibration or deflection by electrical stimulation. The electroactive film 110 is made of a siloxane polymer which is a polymer having electroactivity, and specifically, a siloxane polymer having a fluoro group or a chloro group bonded to a part of the main chain. .

  The siloxane polymer constituting the electroactive film 110 of the present invention has a structure in which a fluoro group or a chloro group having high electronegativity is bonded to the main chain of the siloxane polymer, and a polarization phenomenon occurs in the electroactive film 110. . Thereby, the electroactive film 110 has an improved dielectric constant.

  Since the siloxane polymer of the present invention has a structure similar to polysiloxane used as a conventional dielectric elastomer, it has excellent light transmittance and optical properties. Furthermore, since the siloxane polymer of the present invention has a fluoro group or a chloro group bonded to a part of Si constituting the main chain, it can have the characteristics of a ferroelectric polymer. More specifically, when an external electric field having a predetermined magnitude or more is applied to the electroactive film 110, the Si—F or Si—Cl dipole of the siloxane polymer is selectively arranged in the direction in which the electric field is applied. Thereby, the polarization degree of the electroactive film 110 improves. In addition, even if the external electric field is removed, there is a residual polarization that does not return the Si-F or Si-Cl dipole to its original state. That is, the siloxane polymer of the present invention has properties similar to a ferroelectric polymer such as polyvinylidene fluoride (PVDF). Therefore, the siloxane polymer of the present invention has a higher dielectric constant than conventional dielectric elastomers.

  The siloxane polymer in which a fluoro group or a chloro group is bonded to a part of the main chain of the present invention can be produced by a cross-linking between a polysiloxane having a terminal substituted with a vinyl group and a silicon-based crosslinker. At this time, the fluoro group or chloro group bonded to the main chain of the final siloxane polymer is present in the repeating unit derived from the main chain of the silicon-based crosslinking agent. More specifically, the siloxane polymer having a fluoro group or a chloro group bonded to the main chain of the present invention includes: i) a polysiloxane having a terminal substituted with a vinyl group and a silicon-based crosslink containing a hydrogen or hydroxy group in the main chain Can be prepared by cross-linking the agent and then substituting a hydrogen or hydroxy group with a fluoro group or a chloro group, or (ii) a polysiloxane with a terminal substituted with a vinyl group and a fluoro group in part of the main chain Alternatively, it can be produced by crosslinking a silicon-based crosslinking agent having a chloro group bonded thereto.

  At this time, since the polysiloxane whose terminal is substituted with a vinyl group has the properties of a conventional dielectric elastomer, it imparts the properties of a dielectric elastomer to the siloxane polymer of the present invention. Furthermore, since the fluoro group or chloro group bonded to a part of the main chain has high electronegativity, the dielectric constant is improved by improving the polarization degree of the siloxane polymer of the present invention.

  More specifically, a siloxane polymer in which a fluoro group or a chloro group is bonded to a part of the main chain is represented by a polysiloxane in which a terminal represented by the following chemical formula 1 is substituted with a vinyl group and a chemical formula 2 below. And a part of hydrogen of Si-H or a part of Si-OH present in the main chain of the repeating unit derived from the silicon-based crosslinking agent represented by Formula 2 It can be produced by substituting a hydroxy group with a fluoro group or a chloro group.

In Formula 1, R ₁ and R ₂ are each independently a C _{1 to} C ₂₀ alkyl group, a C _{1 to} C ₂₀ aryl group, a C _{1 to} C ₂₀ cycloalkyl group, or hydrogen, and m is 1 It is an integer above. Although not limited thereto, R ₁ and R _{2 in} Formula 1 are preferably C _{1 to} C ₂₀ alkyl groups, and more preferably methyl groups. m is preferably an integer of 50 to 500.

In Formula 2, R _{3 to} R ₇ are each independently a C _{1 to} C ₂₀ alkyl group, a C _{1 to} C ₂₀ aryl group, a C _{1 to} C ₂₀ cycloalkyl group, or hydrogen, and R ₈ is It is hydrogen or a hydroxy group, n is 0 or an integer of 1 or more, and o is an integer of 2 or more. Although not limited thereto, n is preferably 0 and o is preferably an integer of 10 to 100.

  At this time, specific examples of the alkyl group include methyl group, ethyl group, propyl group, butyl group, sec-butyl group, tert-butyl group, pentyl group, hexyl group, heptyl group, octyl group, nonyl group, Examples include a decyl group, an undecyl group, a dodecyl group, a tridecyl group, a tetradecyl group, a pentadecyl group, a hexadecyl group, a heptadecyl group, an octadecyl group, a nonadecyl group, an icosyl group, a hencicosyl group, and a docosyl group. Specific examples of the aryl group include a phenyl group, tolyl group, biphenyl group, o-, m-, p-terphenyl group, naphthyl group, anthranyl group, phenanthrenyl group, 9-phenylanthranyl group, 9, A 10-diphenylanthranyl group, a pyrenyl group, etc. are mentioned. Specific examples of the cycloalkyl group include a cyclopentyl group, a cyclohexyl group, a norbornane group, an adamantane group, a 4-methylcyclohexyl group, and the like.

  In addition, the siloxane polymer of the present invention is obtained by substituting a fluoro group or a chloro group for a hydrogen or hydroxy group present in the main chain of the silicon-based crosslinking agent represented by the chemical formula 2 so that the main chain is Si-F or Si-Cl. A silicon-based crosslinking agent having a main chain substituted with a fluoro group or a chloro group and a polysiloxane having a terminal represented by the chemical formula 1 substituted with a vinyl group. Can be manufactured.

  The siloxane polymer of the present invention is preferably a copolymer having a network structure. The siloxane polymer produced by the above-described method is produced by crosslinking between a polysiloxane having a terminal substituted with a vinyl group and a siloxane-based crosslinking agent. At this time, the vinyl group present at the terminal of the polysiloxane reacts with Si—H or Si—OH present in the main chain of the siloxane-based crosslinking agent to crosslink in the vertical direction. That is, the polysiloxane whose terminal is substituted with a vinyl group and the siloxane-based crosslinking agent are two-dimensionally bonded to each other to have a continuous network structure that is not a linear structure. Although not limited thereto, a specific example can be confirmed from a siloxane polymer represented by the following chemical formula 3.

In Chemical Formula 3, A represents the structure of Chemical Formula 4. In Formula 4, R ₉ and R ₁₀ are each independently a C _{1 to} C ₂₀ alkyl group, a C _{1 to} C ₂₀ aryl group, a C _{1 to} C ₂₀ cycloalkyl group, or hydrogen, and p is 1 It is an integer above. Although not limited thereto, R ₉ and R ₁₀ in Chemical Formula 4 are preferably C _{1 to} C ₂₀ alkyl groups, and more preferably methyl groups. p is preferably an integer of 50 to 500.

  In this case, in Chemical Formula 3, a represents an example of a repeating unit derived from a siloxane-based crosslinking agent, and b and c represent examples of a repeating unit derived from polysiloxane having a terminal substituted with a vinyl group. As can be confirmed in Chemical Formula 3, the siloxane polymer of the present invention has a network structure.

  In the present invention, the electroactive film 110 made of a siloxane polymer in which a fluoro group or a chloro group is bonded to a part of the main chain may be a stretched film. Although not limited thereto, the electroactive film 110 of the present invention may be uniaxially or biaxially stretched in the MD direction (longitudinal direction) or TD direction (width direction), and is 100% to 500%. It may be stretched at a stretching ratio of. When the electroactive film 110 made of a siloxane polymer having a fluoro group or a chloro group bonded to a part of the main chain is stretched, the fluoro group or the chloro group is arranged in the same direction while the main chain of the siloxane polymer extends. . If fluoro groups or chloro groups are arranged in the same direction, the polarization directions are the same, so that the degree of polarization of the siloxane polymer is further improved and the dielectric constant of the electroactive film 110 is greatly improved.

  More specifically, the siloxane polymer of the present invention can have various crystal structures depending on conditions. Referring to FIG. 2 showing a crystal structure of a siloxane polymer having a fluoro group or a chloro group bonded to a part of the main chain before and after stretching, an unstretched electroactive film exhibits an α-phase. . The α-phase means a state in which a fluoro group or a chloro group is mixed in a trans form and a gauche form by the main chain, so that the degree of polarization of the polymer itself is small. Further, since the fluoro group or the chloro group are arranged so as to face each other in the crystal lattice, the total degree of polarization of the α-phase is offset and the improvement of the dielectric constant of the electroactive film is limited.

  However, as shown in FIG. 2, when the electroactive film is stretched, the main chain of the siloxane polymer is extended, but the steric hindrance between the fluoro group or the chloro group bonded to the main chain of the siloxane polymer is largely eliminated. Thus, a β-phase can be formed in which both the fluoro group and the chloro group are in an all-trans form. That is, fluoro groups or chloro groups are arranged in the same direction in the crystal lattice, and the degree of polarization can be maximized. That is, the stretched electroactive film changes from an α-phase to a β-phase structure. This further improves the dielectric constant of the electroactive film made of the siloxane polymer. Meanwhile, the electroactive film of the present invention may be subjected to a stretching process and a polling process in which atoms having a specific charge are arranged in one direction by applying a high DC voltage to the polymer. The polarization direction of the electroactive film can be formed constant by the poling process.

  In addition, when the electroactive film of the present invention is stretched, a region representing a ferroelectric polymer property and a region representing a dielectric elastomer property are formed separately, and the two regions are alternately formed. (Layer by layer) A stacked structure is obtained.

  More specifically, as shown in FIG. 2, in the electroactive film before stretching, the main chain to which a fluoro group or a chloro group is bonded has an irregular curve, and the fluoro group or the chloro group is in a random direction. Arranged to form an α-phase-like structure. However, since the electroactive film after stretching becomes flat due to attractive force, the main chain to which the fluoro group or chloro group is bonded has a linear shape, and as described above, the fluoro group or chloro group is directed in the same direction. Are arranged. That is, the main chain to which a fluoro group or a chloro group is bonded has a structure similar to that of a conventional ferroelectric polymer such as a PVDF polymer, and thus forms a ferroelectric polymer region. On the other hand, a polymer that bonds between the main chains of the siloxane polymer has a structure similar to that of a conventional dielectric elastomer, and thus forms a dielectric polymer region. Finally, the electroactive film is stretched to form a multilayer structure in which ferroelectric polymer regions and dielectric polymer regions are alternately stacked on each other.

  When the electroactive film 110 has a β-phase structure as described above or forms a multilayer structure in which ferroelectric polymer regions and dielectric polymer regions are alternately stacked, the electroactive film 110 can simultaneously have the properties of a ferroelectric polymer and the properties of a dielectric elastomer, so that the light transmittance, which has been a problem of conventional ferroelectric polymers, is improved. The dielectric constant was greatly improved.

  As described above, the dielectric constant of the electroactive film 110 of the present invention is improved by stretching. Specifically, the electroactive film 110 has a dielectric constant of 15% or more or 20% or more, preferably 30% or more, when stretched with a stretch ratio of 100% or more. In the electroactive film 110, as the draw ratio increases, the atomic arrangement of the fluoro group or chloro group bonded to the main chain of the siloxane polymer becomes more constant, and the degree of polarization improves. Therefore, the dielectric constant of the electroactive film 110 is increased. Is further improved. Specifically, the electroactive film 110 has a dielectric constant improved by 30% or 40% or more, preferably 50% or more, by stretching with a stretching ratio of 300% or more. Thus, the electroactive film 110 of the present invention is formed of a siloxane polymer similar to polydimethylsiloxane (PDMS) conventionally used as a dielectric elastomer, but with Si-F or Si in the main chain of the siloxane polymer. Since —Cl is bonded, the dielectric constant is greatly improved by stretching.

  The electroactive film 110 of the present invention has an excellent dielectric constant, and the dielectric constant measured at 1 kHz under the condition of 25 ° C. is 5.0 or more, preferably 7.0 or more. Polydimethylsiloxane (PDMS), which is most widely used as a dielectric elastomer, generally exhibits a dielectric constant of about 2.5 to 3.0, but the electroactive film 110 of the present invention has a dielectric constant of 7.0 or more. The dielectric constant is expressed, and when the electroactive film 110 is stretched, the dielectric constant is 8.0 or more or 10.0 or more. When the dielectric constant of the electroactive film 110 satisfies the above range, the vibration strength of the touch sensitive element can be improved and the driving voltage can be lowered.

  The electroactive film 110 of the present invention preferably has a light transmittance of 85% or more, and more preferably 90% or more. Generally, in order to arrange a touch sensitive element on the front surface of the display panel, the light transmittance of the touch sensitive element must be 80% or more. In particular, in the case of a ferroelectric polymer such as PVDF (Poly VinylDene Fluoride) and P (VDF-TrFE) (Poly (VinylDene Fluoride) -TriFluorEtyrene) having electric activity, the light transmittance is generally 75% or less. Therefore, there is a problem that it is difficult to arrange on the front surface of the display panel. However, since the electroactive film 110 of the present invention includes both the properties of a ferroelectric polymer and a dielectric elastomer, the electroactive film 110 can function as a touch-sensitive element that is excellent in both light transmittance and dielectric constant.

  The electroactive film 110 of the present invention preferably has a thickness of 10 μm to 500 μm, and more preferably 20 μm to 200 μm. When the thickness of the electroactive film 110 satisfies the above range, strong vibration strength of the touch-sensitive element 100 can be realized.

  A first electrode 121 and a second electrode 122 for supplying power are attached to both surfaces of the electroactive film 110. Specifically, in FIG. 1, the electrode disposed on the lower surface of the electroactive film 110 is illustrated as the first electrode 121, and the electrode disposed on the upper surface of the electroactive film 110 is illustrated as the second electrode 122. .

  The first electrode 121 and the second electrode 122 may be formed of a conductive material, but are not limited thereto, and examples thereof include gold (Au), copper (Cu), and titanium (Ti). , Chromium (Cr), molybdenum (Mo), aluminum (Al), aluminum-copper alloy (Al-Cu alloy) or the like, or PEDOT [Poly (3,4-EthyleneDiOxyThiophene)] : PSS [Poly (4-Styrene Sulfonic acid)], polypyrrole, polyaniline, and the like. In addition, the first electrode 121 and the second electrode 122 may be made of carbon conductive grease, carbon black, or carbon so as to be suitable for smooth and repetitive driving of the touch-sensitive element 100. It may be composed of a soft electrode manufactured by mixing an elastic body with a carbon nanotube (CNT). The first electrode 121 and the second electrode 122 may be made of the same material or different materials.

  When the touch-sensitive element 100 of the present invention is disposed on the display panel, the first electrode 121 and the second electrode 122 may include a transparent conductive material in order to ensure the transparency of the touch-sensitive element. preferable. Although not limited thereto, the transparent conductive material may be selected from the group consisting of indium tin oxide (ITO), graphene, metal nanowires, and transparent conductive oxide (TCO). It can be one kind selected.

  The first electrode 121 and the second electrode 122 are disposed on both surfaces of the electroactive film 110 in various ways. For example, the first electrode 121 and the second electrode 122 may be disposed on both sides of the electroactive film 110 in a manner such as sputtering, printing, slit coating, and the like. . In particular, when the first electrode 121 and the second electrode 122 are disposed of the same material, the first electrode 121 and the second electrode 122 may be disposed at the same time.

  A voltage is applied to the first electrode 121 and the second electrode 122 from the outside to form an electric field. Here, in order to form an electric field on the electroactive film 110, voltages having different magnitudes are applied to the first electrode 121 and the second electrode 122, or voltages having opposite electrical properties. Can be applied. For example, when a positive (+) voltage is applied to the first electrode 121, a negative (−) voltage or a ground voltage is applied to the second electrode 122, and a negative (−) is applied to the first electrode 121. In this case, a positive (+) voltage or a ground voltage may be applied to the second electrode 122. Here, the electrical property of the voltage applied to the first electrode 121 and the electrical property of the voltage applied to the second electrode 122 are changed opposite to each other, whereby the direction of the electric field is also changed. The

  The voltage applied to the first electrode 121 and the second electrode 122 may be an alternating current (AC) voltage or a direct current (DC) voltage. When an alternating voltage (AC) is applied to the first electrode 121 and the second electrode 122, the electroactive film 110 can be periodically displaced, and can exert an oscillating effect. When a direct voltage (DC) is applied to the electrode 121 and the second electrode 122, the electroactive film 110 can maintain a bent state.

  The touch-sensitive element 100 of the present invention uses an electroactive film 110 having an excellent dielectric constant, which includes a siloxane polymer having a fluoro group or a chloro group bonded to at least a part of the main chain. At this time, in the present invention, the touch-sensitive element 100 can use an unstretched electroactive film or a stretched electroactive film as required by the user.

  That is, the unstretched electroactive film and the stretched electroactive film both have a significantly higher dielectric constant than conventional dielectric elastomers used as electroactive polymers. And the vibration strength can be improved.

  As described above, when the electroactive film 110 of the present invention is stretched, a hybrid type polymer partially including a ferroelectric polymer region and a dielectric elastomer region is formed, and the ferroelectric polymer and the dielectric elastomer are formed. These characteristics are expressed simultaneously. More specifically, a ferroelectric polymer region including a fluoro group and a chloro group having a high electronegativity is a dipole inside the ferroelectric polymer region when an electric field is applied to the electroactive film 110. The force is transmitted to the touch sensitive element 100 by changing the alignment direction. Unlike this, the dielectric polymer region is a region where a plurality of polysiloxane chains are formed, and therefore, the dielectric polymer region is an electrostatic attractive force generated by applying a voltage to the electroactive film 110 ( The force is transmitted to the touch-sensitive element 100 by being contracted and expanded by a coulombic force.

  FIG. 3 is a schematic exploded perspective view for explaining the structure of the display device 200 including the touch-sensitive element 100 according to an embodiment of the present invention. As shown in FIG. 3, the display device 200 according to an embodiment of the present invention includes a lower cover 210, a display panel 220, a touch sensitive element 100, a touch panel 230, and an upper cover 240.

  The lower cover 210 is disposed under the display panel 220 so as to cover the lower portions of the display panel 220, the touch sensitive element 100, and the touch panel 230. The lower cover 210 protects the internal configuration of the display device 200 from external impacts and penetration of foreign substances and moisture. For example, the lower cover 210 is not limited thereto, but can be made of a material such as plastic that can be thermoformed and has good workability. Also, the lower cover 210 may be made of a material that can be deformed together with a change in the shape of the display device 200 due to the active development of flexible display devices in recent years. For example, the lower cover 210 may be made of a soft plastic material.

  The display panel 220 means a panel on which display elements for displaying images on the display device 200 are arranged. The display panel 220 is not limited thereto, but various display panels such as an organic light emitting display panel, a liquid crystal display panel, an electrophoretic display panel, and the like can be used. The display panel 220 may be an organic light emitting display device. The organic light emitting display device is a display device that causes an organic light emitting layer to emit light by passing a current through the organic light emitting layer, and emits light of a specific wavelength using the organic light emitting layer. The organic light emitting display device includes at least a cathode, an organic light emitting layer, and an anode.

  The organic light emitting display device may also be configured to be flexible and deformable. That is, the organic light emitting display device is a flexible organic light emitting display device having flexibility, and includes a flexible substrate. The flexible organic light emitting display device can be deformed in various directions and angles by an external force.

  The touch sensitive element 100 may be disposed below the display panel 220 as necessary, and may be disposed above the display panel 220. In FIG. 3, description will be made assuming that the contact-sensitive element 100 is disposed on the upper part. Specifically, the touch-sensitive element 100 can be disposed so as to be in direct contact with the upper surface of the display panel 220, and an adhesive is used between the upper surface of the display panel 220 and the lower surface of the touch-sensitive element 100. It can also be arranged. The adhesive may be, but is not limited to, OCA (Optical Clear Adhesive) or OCR (Optical Clear Resin), but is not limited thereto.

  The touch-sensitive element 100 shown in FIG. 3 includes a first electrode 121, a second electrode 122, and an electroactive film 110. Specific components of the touch sensitive element 100 are the same as those of the touch sensitive element 100 described in FIG.

  The touch sensitive element 100 may be electrically coupled to the display panel 220. For example, an FPCB (Flexible Printed Circuit Board) disposed on the display panel 220 and an electrode of the touch-sensitive element 100 may be electrically coupled to each other through a wiring.

  A touch panel 230 is disposed on the touch sensitive element 100. The touch panel 230 refers to a panel that senses a user's touch input to the display device 200 and performs a function of providing touch coordinates.

  The touch panel 230 can be classified according to the position where it is arranged. For example, an add-on method that adheres to the upper surface of the display panel 220 may be used. In another example, an on-cell method of depositing on the display panel 220 may be used. In another example, an in-cell method formed inside the display panel 220 may be used. In addition, the touch panel 230 can be classified according to an operation method. For example, a capacitive method, a resistive film method, an ultrasonic method, an infrared method, or the like can be used. Preferably, a capacitive touch panel can be used as the touch panel 230.

  In addition, the touch panel 230 can be electrically coupled to the touch sensitive element 100. Specifically, the touch panel 230 is electrically coupled to the electrodes of the touch sensitive element 100, and various touch signals or voltages input from the touch panel 230 can be transmitted to the touch sensitive element 100.

  The upper cover 240 is disposed on the touch panel 230 so as to cover the upper parts of the touch sensitive element 100, the display panel 220, and the touch panel 230. The upper cover 240 can perform the same function as the lower cover 210. The upper cover 240 may be made of the same material as the lower cover 210.

  In addition, the display device 200 has a low driving voltage and an excellent light transmittance by using the electroactive film 110 having an excellent light transmittance and dielectric constant. Therefore, the display device 200 is disposed on the front surface of the display panel. Can do. Thereby, the display apparatus 200 of this invention can transmit a direct touch feeling and feedback to a user.

  FIG. 4 is a diagram illustrating an example in which a display device according to various embodiments of the present invention can be advantageously used. FIG. 4A is an exemplary external view of a mobile display device 300 including a touch-sensitive element according to an embodiment of the present invention. At this time, examples of the mobile display device include small devices such as a smartphone, a mobile phone, a tablet PC, and a PDA. When the touch-sensitive element of the present invention is provided in the mobile display device 300, vibration can be directly transmitted to the user up to a minute difference depending on the touch strength, and a stronger touch feeling can be transmitted. Since the user can feel vibration with touch when performing video viewing, a game, button input, and the like on the mobile display device 300, more user-sympathetic information can be transmitted from the mobile display device 300.

  FIG. 4B is an exemplary external view of a vehicular navigation 400 including a touch-sensitive element according to an embodiment of the present invention. The vehicle navigation 400 may include a display device and a plurality of operation elements, and may be controlled by a processor installed in the vehicle. When the display device of the present invention is applied to the vehicle navigation 400, it is possible to tactilely provide the user with various road heights, road conditions, vehicle progress, and the like.

  FIG. 4C is an exemplary external view of a TV 500 including a touch-sensitive element according to an embodiment of the present invention. When the display device of the present invention is used in a display device such as a TV 500 or a monitor, the user can feel as if he / she actually experiences the texture of a specific property, the state of a speaker, etc. via the display device. , You can enjoy more realistic video.

  FIG. 4D is an exemplary external view of an outdoor advertising board 600 including a touch-sensitive element according to an embodiment of the present invention. When the display device of the present invention is applied to the outdoor advertising board 600, tactile information about the advertising article to be sold can be directly transmitted to the user, so that the advertising effect can be maximized.

  FIG. 4E is an exemplary external view of a slot machine 700 including a touch-sensitive element according to an embodiment of the present invention. The slot machine 700 may include a display device and a housing in which various processors are incorporated. When the display device of the present invention is applied to the slot machine 700, by directly operating the image, lever pulling, rotation of the roulette wheel, movement of the roulette ball, etc. can be provided realistically, and the feeling of immersion in the game can be doubled. it can.

  FIG. 4F is an exemplary external view of an electronic blackboard 800 including a touch-sensitive element according to an embodiment of the present invention. The electronic blackboard 800 may include a display device, a speaker, and a structure for protecting them from external impacts. When the display device of the present invention is applied to the electronic blackboard 800, an educator may be provided with a feeling of writing on the blackboard 800 directly when inputting lecture contents to the display device with a stylus pen or a finger. In addition, when the educated person applies touch input to the image displayed on the electronic blackboard 800, tactile feedback suitable for the image can be provided to the educated person, so that the educational effect can be maximized.

  5A and 5B are flowcharts illustrating a method for manufacturing an electroactive film made of a siloxane polymer having a fluoro group or a chloro group bonded to a part of a main chain according to various embodiments of the present invention.

  The method for producing an electroactive film of the present invention is different depending on the method for producing a siloxane polymer containing a halogen element. As described below, the method for producing a siloxane polymer is separated into two methods. To do.

  Specifically, the method for producing an electroactive film according to FIG. 5A includes a siloxane polymer obtained by crosslinking polysiloxane having a terminal substituted with a vinyl group and a silicon-based crosslinking agent containing Si—H or Si—OH in the main chain. Is prepared, and the step of replacing the remaining Si—H or Si—OH of the repeating unit derived from the silicon-based crosslinking agent with a fluoro group or a chloro group is included.

  First, a polysiloxane represented by the following chemical formula 1 and a silicon-based crosslinking agent represented by the following chemical formula 2 are cross-linked to produce a siloxane polymer (S51a).

In Formula 1, R ₁ and R ₂ are each independently a C _{1 to} C ₂₀ alkyl group, a C _{1 to} C ₂₀ aryl group, a C _{1 to} C ₂₀ cycloalkyl group, or hydrogen, and m is 1 It is an integer above. Although not limited thereto, R ₁ and R _{2 in} Formula 1 are preferably C _{1 to} C ₂₀ alkyl groups, and more preferably methyl groups. m is preferably an integer of 50 to 500.

In Formula 2, R _{3 to} R ₇ are each independently a C _{1 to} C ₂₀ alkyl group, a C _{1 to} C ₂₀ aryl group, a C _{1 to} C ₂₀ cycloalkyl group, or hydrogen, and R ₈ is It is hydrogen or a hydroxy group, n is 0 or an integer of 1 or more, and o is an integer of 2 or more. Although not limited thereto, n is preferably 0 and o is preferably an integer of 10 to 100.

  The polysiloxane represented by the chemical formula 1 is a polysiloxane having a terminal substituted with a vinyl group, and the cross-linking agent represented by the chemical formula 2 is a chain-type silicon-based crosslinking containing Si—H or Si—OH in the main chain. It is an agent. Although not limited thereto, Chemical Formula 1 may be obtained by replacing the terminal of polydimethylsiloxane (PDMS) with a vinyl group, and Chemical Formula 2 is a polyhydrogenmethyl having a terminal substituted with trimethylsilane as a crosslinking agent. Siloxane (PHMS) may be used.

  In the step (S51a) for producing the siloxane polymer, benzene, toluene, n-heptane, ether, xylene, triethylamine, diisopropylamine and the like can be used as the organic solvent, and the temperature is 50 to 80 ° C. for 1 to 48 hours. Can be done during.

The step (S51a) of producing the siloxane polymer can be performed under a platinum-based catalyst. Examples of the platinum-based catalyst include, but are not limited to, Pt which is a Carstedt's catalyst. [(CH ₂ ═CH—SiMe ₂ ) ₂ O] _1.5 , Pt [(C ₂ H ₄ ) Cl ₂ ] ₂ which is a Zeise salt dimmer, and the like can be used. Such a catalyst can be used as a content of 0.01 mol% to 1 mol% with respect to 1 mol of the reactant.

  At this time, the volume ratio for crosslinking the crosslinking agent represented by Chemical Formula 2 to the polysiloxane represented by Chemical Formula 1 is preferably in the range of 9: 1 to 5: 5, and is 8: 2 to 6: 4. More preferably, it is in the range. When the silicon-based crosslinking agent represented by the chemical formula 2 is less than the above range, sufficient crosslinking may not be performed. When the silicon cross-linking agent is over the above range, the hardness is excessively increased and the contact-sensitive element is used. May not be appropriate for

In the step (S51a) of producing the siloxane polymer, the vinyl group present at the terminal of the polysiloxane represented by the chemical formula 1 is a silicon-based crosslinking agent represented by the chemical formula 2 while the double bond of the vinyl group is released. It binds to a part of hydrogen of Si—H present in the main chain or a part of hydroxyl group of Si—OH. That is, in the silicon-based crosslinking agent represented by the chemical formula 2, the polysiloxane does not react with the substituents of R _{5 to} R ₇ , and the reaction proceeds by crosslinking with the hydrogen or hydroxy group of R ₈ .

  As described above, the siloxane polymer resulting from such a crosslinking reaction forms a network structure.

  Next, a part of hydrogen or hydroxy group bonded to the main chain of the siloxane polymer produced from the step (S51a) for producing the siloxane polymer is substituted with a fluoro group or a chloro group (S52a).

In the step of substituting with a fluoro group or a chloro group (S52a), among the hydrogen of Si—H or the hydroxy group of Si—OH present in the main chain of the siloxane polymer produced through the step of producing a siloxane polymer (S51a) , At least a portion is substituted with a fluoro group or a chloro group. More specifically, the step of substituting with a fluoro group or a chloro group (S52a) is performed by repeating the Si—H hydrogen or Si—OH hydroxy group of the repeating unit derived from the silicon-based cross-linking agent represented by Formula 2. Of these steps, at least a part is substituted with a fluoro group or a chloro group. That is, in the step (S51a) of producing the siloxane polymer, the hydrogen or hydroxy group of R ₈ of the chemical formula 2 remaining after the reaction with the vinyl group present at the end of the polysiloxane represented by the chemical formula 1 is replaced with a fluoro group or a chloro group. Is done.

Although not limited thereto, the siloxane polymer produced in the step (S51a) of producing the siloxane polymer is reacted with an aqueous solution of hydrogen fluoride (HF) or hydrogen chloride (HCl), or Cl ₂ and F ₂ gases. Si—H or Si—OH can be replaced with Si—F or Si—Cl by injecting and reacting.

  Next, the substituted siloxane polymer is formed as an electroactive film (S53a). Substituted siloxane polymers include, but are not limited to, coatings such as spin coating, dip coating, solvent casting, slit coating, and bar coating on various substrates such as glass, ITO, and plastic. Using a method or a coextrusion method, the film can be formed in a film form.

  Next, the present invention may further include a step of stretching the manufactured electroactive film (S54a). The step (S54a) of stretching the electroactive film is for switching the α-phase to the β-phase, and is performed by a method of stretching the electroactive film manufactured from the step S53a in a certain direction. The stretching methods are roughly classified into a wet stretching method and a dry stretching method. The dry stretching method is further classified into an inter-roll stretching method, a heating roll stretching method, a compression stretching method, a tenter stretching method, and the like. The wet stretching method is further classified into a tenter stretching method, an inter-roll stretching method, and the like. In the present invention, both the wet stretching method and the dry stretching method can be used, and if necessary, they can be used in combination.

  At this time, the electroactive film can be stretched along one axis (one direction) in the MD direction (longitudinal direction) or the TD direction (width direction) as necessary, for example, biaxial (two directions). It can also be stretched along. The biaxial stretching may be performed sequentially or simultaneously.

  In the step of stretching the electroactive film (S54a), the electroactive film is preferably stretched at a stretch rate of 100% to 500%. This is because when the stretch ratio is less than 100%, the electroactive film is difficult to be completely switched to the β-phase, and when the stretch ratio exceeds 500%, the film is broken or a sufficient thickness is secured. This is because it is difficult.

  In order to stabilize the optical properties and mechanical properties of the electroactive film, a heat treatment (annealing) or the like can be performed after the stretching treatment. The heat treatment conditions are not particularly limited, and any appropriate conditions known in the art can be adopted.

  Next, a method of manufacturing an electroactive film according to FIG. 5B is for manufacturing a siloxane polymer after first substituting a silicon-based crosslinking agent containing Si—H or Si—OH in the main chain with a fluoro group or a chloro group. Cross-linking the substituted silicon-based cross-linking agent with the polysiloxane having a terminal substituted with a vinyl group.

As shown in FIG. 5B, first, at least a part of the hydrogen or hydroxy group bonded to the main chain of the silicon-based crosslinking agent represented by Chemical Formula 2 is substituted with a fluoro group or a chloro group (S51b). Compared with FIG. 5A, before cross-linking the polysiloxane represented by Chemical Formula 1 and the silicon-based crosslinking agent represented by Chemical Formula 2, the hydrogen present in the main chain of the silicon-based crosslinking agent represented by Chemical Formula 2 Or there is a difference in that a part of the hydroxy group is substituted with a fluoro group or a chloro group. That is, part of the hydrogen or hydroxy group of R _{8 in} Chemical Formula 2 is substituted with a fluoro group or a chloro group.

Although not limited thereto, the silicon-based crosslinking agent represented by Chemical Formula 2 is reacted with an aqueous solution of hydrogen fluoride (HF) or hydrogen chloride (HCl), or the reaction is performed by injecting Cl ₂ and F ₂ gas. By doing so, at least part of Si—H or Si—OH can be replaced with Si—F or Si—Cl.

  Next, the substituted crosslinking agent and the polysiloxane represented by Chemical Formula 1 are crosslinked to produce a siloxane polymer (S52b). At this time, the method of crosslinking the silicon-based crosslinking agent substituted with a fluoro group or a chloro group and the polysiloxane represented by Formula 1 is substantially the same as the step S52a disclosed in FIG. 5A. The duplicate explanation for is omitted.

  Next, a siloxane polymer is formed as an electroactive film (S53b). In addition, the method may further include stretching the manufactured electroactive film (S54b).

  The step of forming the electroactive film and the step of stretching the manufactured electroactive film are substantially the same as S53a and S54a disclosed in FIG.

  In the following, the production of a siloxane polymer and an electroactive film comprising a siloxane polymer will be described in more detail through examples.

Production Example: Production of Siloxane Polymer with Fluoro Group Bonded to Main Chain After dispersing 10 g of polyhydrogenmethylsiloxane (PHMS, weight average molecular weight: 3000) as a silicon-based crosslinking agent in 100 ml of toluene solvent, At 80 ° C., 30 ml of 1 molar HF was added and treated for 3 hours to produce polyhydrogenmethylsiloxane having fluoro (F) bonded to the main chain. Thereafter, polydimethylsiloxane having a terminal substituted with a vinyl group (PDMS, weight average molecular weight: about 40,000) and polyhydrogenmethylsiloxane having fluoro (F) bonded to a part of the main chain were prepared 7: 3. A siloxane polymer was prepared by mixing at a volume ratio of

Example 1
The siloxane polymer produced according to the production example was applied to a glass substrate by a bar coating method and then treated at 60 ° C. for 2 hours to produce an unstretched electroactive film composed of the siloxane polymer.

(Example 2)
9: 1 volume of polydimethylsiloxane having a terminal substituted with a vinyl group (PDMS, weight average molecular weight: about 40,000) and polyhydrogenmethylsiloxane having fluoro (F) bonded to a part of the main chain produced An unstretched electroactive film was produced in the same manner as in Example 1 except that the siloxane polymer was produced by mixing at a ratio.

(Comparative Example 1)
Instead of the electroactive film of Example 1, polydimethylsiloxane (PDMS) was applied as a dielectric elastomer onto the substrate, and then dried to obtain an unstretched electroactive film.

(Comparative Example 2)
An unstretched electroactive film was produced by a bar coating method using a polydimethylsiloxane-based polymer (trade name: Dow 730, Dow Corning) represented by the following chemical formula 5, which was not a siloxane polymer produced according to Production Example.

(Comparative Example 3)
Instead of the electroactive film of Example 1, an electroactive film made of a ferroelectric polymer P (VDF-TrFE) (Poly (Vinylene Fluoride) -TriFluorEtyrene) was used.

Experimental Example 1: Measurement of dielectric constant and measurement of change in dielectric constant due to stretching The dielectric constants of the electroactive films of Examples 1-2 and Comparative Examples 1-2 were measured at 25 ° C. and a frequency of 1 kHz using an LCR meter (4284A). The capacitance was measured and calculated by using the following formula 6.

Where ε is the dielectric constant, C is the capacitance, ε _o is the vacuum dielectric constant, t is the thickness of the electroactive film, and A is the contact cross-sectional area of the electrode.

  Next, the electroactive films of Examples 1 and 2 and Comparative Examples 1 and 2 are stretched by 100%, 300%, and 400%, respectively, in the MD direction (longitudinal direction) using an inter-roll stretching method. The film was uniaxially stretched at a rate. The dielectric constant and the rate of change of the dielectric constant of each stretched electroactive film were measured. The measurement results are shown in Table 1 below.

  As confirmed through Table 1, the electroactive films of Examples 1 to 2 are significantly higher than polydimethylsiloxane (PDMS) that has been used as a conventional dielectric elastomer as in Comparative Example 1. It was confirmed that it had a dielectric constant. In addition, the dielectric constant of the electroactive film made of the siloxane polymer of the present invention is such that the dielectric constant after stretching at a stretching ratio of 100% or more is improved by 30% or more compared to the dielectric constant before stretching, and is 300% or more. It was confirmed that the dielectric constant after stretching at a stretching ratio was improved by 40% or more compared to the dielectric constant before stretching. Moreover, it has been confirmed that a high dielectric constant that is difficult for conventional polysiloxanes can be achieved.

  Unlike this, as confirmed in Comparative Example 1, it was found that the dielectric constant of the electroactive film made of polydimethylsiloxane (PDMS) was not improved by stretching.

  Further, comparing Example 1 with Comparative Example 1 and Comparative Example 2, the dielectric constant of the electroactive film of Comparative Example 2 is higher than that of Comparative Example 1. However, the dielectric constant of the electroactive film of Comparative Example 2 is lower than that of Example 1. In the case of the electroactive film of Comparative Example 2, it was confirmed that the effect of improving the dielectric constant by stretching was weak as in Example 1. Such a difference results from the difference in polymer structure between the electroactive film of Comparative Example 2 and the electroactive film of Example 1. As can be seen from Chemical Formula 5, the electroactive film of Comparative Example 2 is similar to the electroactive film of Example 1 in that it is composed of a polydimethylsiloxane-based polymer containing a fluoro group. However, the electroactive film of Comparative Example 2 is different from Example 1 in which the fluoro group is directly bonded to the main chain, and is different in that the fluoro group is bonded to the branched chain. In other words, unlike the electroactive film of Example 1, the electroactive film of Comparative Example 2 is unlikely to be expected to have the effect that the fluoro groups are aligned in the same direction by stretching. Extreme and dielectric constant does not improve.

Experimental Example 2: Light transmittance measurement The light transmittance of the electroactive films of Examples 1-2 and Comparative Examples 1 and 3 was measured using a haze meter (JCH-300S, Oceanoptics). The measurement results are shown in Table 2 below.

  As confirmed through Table 2, in Examples 1 to 2, not only the dielectric constant is remarkably improved as compared with the conventional dielectric elastomer, but also light transmission compared to the ferroelectric polymer (Comparative Example 3). It was confirmed that the rate was remarkably excellent. Accordingly, the electroactive film of the present invention can be disposed on the front surface of the display panel with a significantly improved dielectric constant while having excellent light transmittance similar to that of the dielectric elastomer. That is, the touch-sensitive element including the electroactive film of the present invention can provide direct and various tactile feedback to the user.

Experimental Example 3: Performance Evaluation of Contact Sensitive Element In order to evaluate the performance of the touch sensitive element including the electroactive film of the present invention, vibration acceleration was measured. 6A to 6C are vibration acceleration experimental data for Example 1 and Comparative Example 1. FIG. Specifically, FIG. 6A is a diagram showing a graph of vibration acceleration measured when a voltage of 2 kVpp is applied to a touch-sensitive element including an unstretched electroactive film manufactured according to Example 1. FIG. 6B shows a case where a voltage of 2 kVpp is applied to a contact-sensitive element including an electroactive film manufactured according to Example 1 and stretched at a stretch rate of 300% in the MD direction (longitudinal direction) using the inter-roll stretching method. It is a figure which shows the graph of the vibration acceleration measured by this. FIG. 6C is a graph showing a vibration acceleration measured when a voltage of 2 kVpp is applied to the touch-sensitive element of Comparative Example 1.

  As shown in FIG. 6C, when a 2 kVpp voltage was applied to the touch-sensitive element of Comparative Example 1, a vibration acceleration of 0.11 G was generated by the actuation, but as shown in FIG. When a 2 kVpp voltage is applied to the contact-sensitive element including the unstretched electroactive film, a vibration acceleration of 0.16 G was generated by actuation, so that it can be confirmed that the vibration acceleration was larger than that of Comparative Example 1. In addition, as shown in FIG. 6B, when a 2 kVpp voltage is applied to the contact-sensitive element including the stretched electroactive film, it was confirmed that the vibration acceleration was further increased because the vibration acceleration of 0.24 G was measured. It was.

  As described above, the embodiments of the present invention have been described in more detail with reference to the accompanying drawings. However, the present invention is not necessarily limited to such embodiments, and does not depart from the technical idea of the present invention. Various modifications can be made. Therefore, the embodiments disclosed in the present invention are not intended to limit the technical idea of the present invention, but are for explanation. The scope of the technical idea of the present invention is limited by such an embodiment. It is not something. The protection scope of the present invention must be analyzed by the following claims, and all technical ideas within the scope equivalent thereto must be analyzed to be included in the scope of the right of the present invention. Let's go.

Claims (8)

Comprising an electroactive film comprising a siloxane polymer having a fluoro group or a chloro group bonded to at least a portion of the main chain;
The electroactive film is a touch sensitive element having a β-phase structure .   The siloxane polymer is produced by crosslinking (i) a polysiloxane having a terminal substituted with a vinyl group and a silicon-based crosslinking agent having a fluoro group or a chloro group bonded to at least a part of the main chain, or (Ii) After cross-linking a polydimethylsiloxane (PDMS) having a terminal substituted with a vinyl group and a silicon-based crosslinking agent containing hydrogen or a hydroxy group in the main chain, at least a part of the hydrogen or hydroxy group is a fluoro group or The touch-sensitive element according to claim 1, which is produced by substitution with a chloro group.   The touch-sensitive element according to claim 1, wherein the electroactive film is uniaxially or biaxially stretched. The touch-sensitive element according to claim 3 , wherein the electroactive film has a multilayer structure in which ferroelectric polymer regions and dielectric polymer regions are alternately laminated. The touch-sensitive element according to claim 3 , wherein the electroactive film has a dielectric constant measured at 1 kHz of 7.0 or more.   The touch-sensitive element according to claim 1, wherein the electroactive film has a light transmittance of 85% or more. A display device having a display panel, a touch panel, and a touch sensitive element,
The contact-sensitive element includes an electroactive film including a siloxane polymer having a fluoro group or a chloro group bonded to at least a part of a main chain,
The electroactive film is a display device having a β-phase structure . The display device according to claim 7 , wherein the electroactive film is uniaxially or biaxially stretched.

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